The present invention relates to improvements in windmills of the type having vertically extending wind reaction panels supported by spars extending radially of a vertically disposed, rotatable output or drive shaft, and more particularly towards improvements in vertical axis windmills of the type fitted with a plurality of wind reaction panels non-movably fixed to their associated spars.
In copending U.S. patent application Ser. No. 450,795, filed Dec. 17, 1982, and now abandoned, there is disclosed a vertical axis windmill having a wind vane assembly including a wind vane primarily intended for use in positionally locating a cam plate serving to effect rotational movements of wind reaction panels relative to their associated supporting spars, during that portion of the rotational movement of the spars in a direction relatively towards the oncoming wind. An additional feature of such wind vane assembly is the provision of a shield plate positioned to block or redirect the oncoming wind, so as to minimize drag on the spars and panels during rotational movement of the spars relatively towards the wind. The wind shield is preferably formed with a plurality of vertically extending, fixed position louvers, which serve to direct wind passing through slot openings formed in the shield plate for travel in a direction extending generally tangentially of the path of travel of the outer ends of the spars in a direction of rotation thereof, as such ends pass through the eye of the oncoming wind. Further, a wind speed sensing device carried by the wind vane may be employed to produce control signals characteristic of various wind loading conditions, which in turn control operation of a power generator unit of the windmill for purposes of preventing excessive rotational speed of the spars.